// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_HANDLE_H_
#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_HANDLE_H_

#include <memory>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "content/browser/service_worker/service_worker_version.h"
#include "content/common/content_export.h"
#include "content/common/service_worker/service_worker_types.h"

namespace content {

class ServiceWorkerContextCore;

// Roughly corresponds to one WebServiceWorker object in the renderer process.
//
// The renderer process maintains the reference count by owning a
// ServiceWorkerHandleReference for each reference it has to the service worker
// object. ServiceWorkerHandleReference creation and destruction sends an IPC to
// the browser process, which adjusts the ServiceWorkerHandle refcount.
//
// Has references to the corresponding ServiceWorkerVersion in order to ensure
// that the version is alive while this handle is around.
class CONTENT_EXPORT ServiceWorkerHandle
    : NON_EXPORTED_BASE(public ServiceWorkerVersion::Listener) {
public:
    // Creates a handle for a live version. This may return nullptr if any of
    // |context|, |provider_host| and |version| is nullptr.
    static std::unique_ptr<ServiceWorkerHandle> Create(
        base::WeakPtr<ServiceWorkerContextCore> context,
        base::WeakPtr<ServiceWorkerProviderHost> provider_host,
        ServiceWorkerVersion* version);

    ServiceWorkerHandle(base::WeakPtr<ServiceWorkerContextCore> context,
        base::WeakPtr<ServiceWorkerProviderHost> provider_host,
        ServiceWorkerVersion* version);
    ~ServiceWorkerHandle() override;

    // ServiceWorkerVersion::Listener overrides.
    void OnVersionStateChanged(ServiceWorkerVersion* version) override;

    ServiceWorkerObjectInfo GetObjectInfo();

    int provider_id() const { return provider_id_; }
    int handle_id() const { return handle_id_; }
    ServiceWorkerVersion* version() { return version_.get(); }

    int ref_count() const { return ref_count_; }
    bool HasNoRefCount() const { return ref_count_ <= 0; }
    void IncrementRefCount();
    void DecrementRefCount();

private:
    base::WeakPtr<ServiceWorkerContextCore> context_;
    base::WeakPtr<ServiceWorkerProviderHost> provider_host_;
    const int provider_id_;
    const int handle_id_;
    int ref_count_; // Created with 1.
    scoped_refptr<ServiceWorkerVersion> version_;

    DISALLOW_COPY_AND_ASSIGN(ServiceWorkerHandle);
};

} // namespace content

#endif // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_HANDLE_H_
